On a mid-April day last year, Glenn Beck was in a full lather. Less than one week had passed since a pair of bombs had exploded at the Boston Marathon, killing three and injuring hundreds more. The FBI had just identified the Tsarnaev brothers as primary suspects behind the attack. But to Beck, cloaked in a gray button-down and a sheen of indignation, this wasn’t enough.

In attendance at the marathon had been a 20-year-old Saudi Arabian student named Abdulrahman Alharbi. He was on a full ride to study at the nearby New England School of English. He’d been injured at the marathon, later questioned by police and ultimately cleared of wrongdoing.

Beck, however, had suspicions. The radio host urged the U.S. government to release information on Alharbi or Beck would “expose” him. “Let me send this message very clear,” said Beck, who left Fox News in 2011. “We know who this Saudi national is…. We know who this man is and, listen to me carefully, we know he is a very bad, bad, bad man.”

Beck continued days later: “While the media continues to look at what the causes were [behind] these two guys, there are, at this hour, three people involved,” he said, alleging the U.S. government had “tagged” Alharbi as a “proven terrorist.”

The broadcaster eventually called Alharbi an al-Qaeda “control agent” and the “money man” behind the attacks. “You know who the Saudi is?” Beck asked. “He’s the money man. He’s the guy who paid for it.”

“Is this speculation or are you reporting something?” a co-host asked.

Beck ignored the question. “He’s the money man.”

The “money man” has now filed a defamation suit against Beck, who has made a career out of conspiratorial musings. Beck has not responded publicly to the suit, which was filed Friday in U.S. District Court in Boston. He had not responded to e-mails from The Washington Post as of early this morning.

“Alharbi, like many others, was questioned by federal authorities investigating the events of that day,” says the lawsuit. “The authorities quickly concluded that Mr. Alharbi, other than being injured in the attacks, had no involvement.

“Beck repeatedly and falsely identified Mr. Alharbi as an active participant, repeatedly questioned the motives of federal officials in failing to pursue or detain Alharbi and repeatedly and falsely accused Mr. Alharbi of being a criminal who had funded the attacks,” the lawsuit says.

Beck’s allegations added to a cacophony of misinformation that rose out of the Boston bombings, as anonymous Redditors vented unsubstantiated suspicions, and the New York Post plastered its own accusations on the paper’s cover. (The New York Post was sued for defamation in Massachusetts court over the matter, and the case is pending.)

Beck, normally a frenetic tweeter, has remained quiet since the lawsuit was filed.

The host’s allegations have haunted the Saudi student, according to the complaint. “Alharbi has received numerous messages, internet postings and other communications based on Beck’s false statements accusing him of being a murderer, child killer and terrorist.”

Alharbi told the Islamic Monthly in May that such accusations have left him changed forever. “All the police officers and the FBI … and all the nurses and all the doctors were staring at me…. I was looking [at] them like, is it because of the color of my skin, or is it because of the name of my country?”